[Mrpalmere]

Generally, 6 WD designed machines have the center wheel on each side lower by a bit to make turning easier therefore giving better control. Lowering the center wheel does not make the outside wheels be off the floor but rather lowers the pressure force on those wheels. Should the machine be unbalanced to one end then the center and heavier end would be giving the greatest driving forces and allow for better control than having the four wheels on the corners because of a tighter radius for turning.

I think this makes sense, we have had good results using 6WD, and according to some is the premium and preferred method for FRC machines.